Tetroxyrhina dentata Shi, Gaimari & Yang, 2017, sp. nov.

Tetroxyrhina dentata sp. nov.

(Figs 5–8, 42–45)

Diagnosis. Frons with a broad brown stripe extending to ocellar triangle. Arista brown, pubescent. Fore tarsomeres 3–5 brown, mid and hind tarsomeres 4–5 pale brown. Wing intensely brown along costal margin; a weak brown spot on each of crossveins r-m and dm-cu. Abdomen yellow, tergites 1–6 each with a pair of blackish brown triangular lateral spots; female tergite 7 entirely brown on posterior margin.

Description. MALE. Body length 3.9–4.1 mm, wing length 3.6–3.8 mm. FEMALE. Body length 4.1 mm, wing length 3.6 mm.

Head (Figs. 42–43) yellow. Frons with a broad brown stripe extending to ocellar triangle, and black short setulae on anterior 2/3, nearly 1.5 times longer than wide and parallel-sided; ocellar triangle blackish gray; anterior fronto-orbital setae reclinate, slightly shorter than the posterior. Facial keel distinct on upper part between bases of antennae; gena about 1/2 height of eye, with a wide brown stripe. Antenna brownish yellow (antennae broken off in female), 1st flagellomere rounded apically, nearly 1.6 times longer than high; arista brown, pubescent. Orbitoantennal spot distinct, present as a black rectangular spot between eye and antenna. Proboscis mostly yellow except pale brown at tip, with yellow and blackish setulae; palpus yellow with black setulae.

Thorax (Figs. 42–43) yellow and brown with sparse grayish white pruinosity. Mesonotum pale brown with narrow yellow dorsocentral vittae and a narrow yellow median vitta, area adjacent to scutellum yellow; scutellum pale yellow with pair of narrow pale brown stripes; 0+3 dorsocentral setae, acrostichal setulae in 4 rows; prescutellar acrostichal seta shorter than 1st postsutural dorsocentral seta; anepisternum pale brown except slightly yellow on upper margin, and katepisternum blackish brown with sparse grayish white pruinosity; 1 anepisternal seta, 1 katepisternal seta. Legs mostly yellow, except fore tarsomeres 3–5 brown, mid and hind tarsomeres 4–5 pale brown. Fore femur with 5 posteroventral setae, 8 posterodorsal setae; fore tibia with 1 preapical anterodorsal seta and 1 weak apicoventral seta. Mid femur with 1 weak apicoposterior seta; mid tibia with 1 strong preapical anterodorsal seta, 1 strong apicoventral seta. Hind femur with 1 weak preapical anterodorsal seta; hind tibia with 1 preapical anterodorsal seta and 1 short apicoventral seta. Wing (Fig. 44) slightly darkened hyaline, with darker brown along costal margin; a weak brown spot on each of crossveins r-m and dm-cu; subcostal cell brown; costa with 2nd (between R1 and R2+3), 3rd (between R2+3 and R4+5) and 4th (between R4+5 and M1) sections in proportion of 6.3: 1.3:1; crossvein r-m beyond middle of discal cell; ultimate and penultimate sections of M 1 in proportion of 1:1.2; ultimate section of CuA1 about 1/5 of penultimate. Halter yellow except knob black.

Abdomen (Fig. 42) yellow in dorsal view, tergites 1–6 each with a pair of blackish brown triangular lateral spots; female tergite 7 entirely brown on posterior margin; male sternite 6 membranous with an associated pair of triangular sclerites. Male genitalia (Figs 5–8, 45): epandrium triangular, with a pair of black conical dorsoapical processes in lateral view and a tiny ventral incision in posterior view; surstylus with short setulae; hypandrium broad, with a tiny concavity on two lateral processes; phallus consisting of a pair of claviform sclerites, with apical teeth in lateral view.

Type material. Holotype male (CAUC), CHINA, Yunnan Province: Mengla, Menglun zhiwuyuan, 570 m, 22. IV. 2007, Hui Dong. Paratypes: 1 male (CAUC), CHINA, Yunnan Province: Menglun, No. 55 area, 920 m, 31. V. 2007, Wenliang Li; 1 female (CAUC), CHINA, Yunnan Province: Mengla, Menglun zhiwuyuan, 570 m, 22. IV. 2007, Hui Dong.

Distribution. China (Yunnan).

Remarks. The new species is very similar to Tetroxyrhina forficula Shatalkin from Japan in having a yellow palpus, and the wing being intensely brown along the costal margin, but it can be separated from the latter by fore tarsomeres 3–5 being brown; the wing having a weak brown spot on each of crossveins r-m and dm-cu; the abdomen being yellow, tergites 1–6 each having a pair of blackish brown triangular lateral spots; and female tergite 7 being entirely brown on posterior margin. In Tetr. forficula, only fore tarsomeres 2–5 are brown; the wing has a distinct brown cloud on each of crossveins r-m and dm-cu; and the abdominal tergites are blackish brown with blurry longitudinal stripes in dorsal view (Shatalkin, 1997).

Etymology. Latin, dentata, meaning toothed, referring to the phallus with apical teeth in lateral view; a feminine adjective.